The search ability of the function discovery system named S-System has been improved in this paper. In the system. there exist many individuals called bugs. Two strategies for improving the search ability are introduced: (a) when a bug moves in a direction that lowers the fitness, it turns back, and (b) only a limited number of bugs can exist in a phylum. Strategy (a) shortens the number of generations required in finding the true function and strategy (b) improves the discovery rate. The effectiveness of these strategies is confirmed by implementing them in a problem of finding Kepler's law using the S-System.